systemd also listening on imaps port

[Kai Schaetzl]

I noticed that most of the time with dovecot 2.3 I get this output, 
showing systemd listening on the port as well:

lsof -i TCP:993
systemd     1 root   38u  IPv4 3388360574      0t0  TCP *:imaps (LISTEN)
systemd     1 root   41u  IPv6 3388360575      0t0  TCP *:imaps (LISTEN)
dovecot 11607 root    5u  IPv4 3388360574      0t0  TCP *:imaps (LISTEN)
dovecot 11607 root    6r  IPv6 3388360575      0t0  TCP *:imaps (LISTEN)

Sometimes I don't get the extra systemd lines, but I can't reproduce it 
now. It's only for port 143 and 993. Other ports show only two dovecot 
processes. Operation seems to be normal.

Is this how it is supposed to be with dovecot 2.3?
This is Ubuntu 16.04.